As many as 6,500 bowel cancer patients could be denied access to life-extending drugs when a cash pot to pay for them ceases to exist at the end of the year, a charity has warned.

The Cancer Drugs Fund, worth £200 million a year, was set up for patients in England to access drugs approved by their doctors but not given the go-ahead for widespread use on the NHS.

The aim of the fund was to make it easier for doctors to prescribe treatments even if they have not yet been approved by the National Institute for health and Clinical Excellence (NICE).

The scheme is set to run until 2014, but charity Beating Bowel Cancer has raised concerns about the availability of the drugs after this period.

A spokeswoman said that 6,427 patients every year could be denied access to the medicines when the cash flow dries up.

The charity is calling on ministers to create a “workable alternative” to provide the drugs to patients beyond January 2014.

“The Cancer Drugs Fund has improved access to vital medicines for thousands of bowel cancer patients, many of whom wouldn’t be alive today if they hadn’t had the treatment,” said charity chief executive Mark Flannagan.

“However, we’re very worried that the clock is ticking for future bowel cancer patients.

“The uncertainty around how these drugs will be funded in the years to come will mean patients who could benefit from having treatment in the future, may be denied access because the money isn’t there to fund it.

“It is vital that the funding remains in place to ensure that bowel cancer patients will continue to get access to the drugs which their doctors say they need on the NHS.

“Without it we fear patients’ lives will be put at risk. We simply can’t go backwards to a time when cancer patients had to beg for life-extending treatment.”

Earlier this week it emerged that bowel cancer rates among men have soared by more than a quarter in the last 35 years.

Incidence of the disease has climbed from 45 cases per 100,000 men in 1975-77 to 58 cases in 2008-10, a rise of 29 per cent, said Cancer Research UK.

Over the same time period, rates for women have increased only slightly from 35 to 37 per 100,000.

Increasing rates of bowel cancer may be linked to obesity and diets high in red and processed meat and low in fibre. Another key factor is the increasing age of the population. But why there should be such a stark difference between men and women is still unknown.

Bowel cancer is the second most common cause of cancer death in the UK after lung cancer.